JP7090605B2 - Motors, compressors and air conditioners - Google Patents

Description

The present invention relates to motors, compressors and air conditioners.

There are two types of winding of the stator winding in the motor: centralized winding and distributed winding. In electric motors used in air conditioners and the like, distributed windings, which are more advantageous for suppressing noise and vibration than centralized windings, are often used.

Concentric windings are often used among distributed windings, but Patent Document 1 and Patent Document 2 disclose those using a wave winding having a coil end portion smaller than that of the concentric windings.

JP-A-2015-136195 (see FIG. 3) JP-A-2015-126628 (see FIGS. 1 to 3)

On the other hand, when a motor is used for a compressor, it is necessary not only to suppress vibration and noise, but also to provide a passage for a refrigerant inside the motor to secure a sufficient flow rate of the refrigerant when the motor is operated.

The present invention has been made to solve the above problems, and an object of the present invention is to suppress vibration and noise and to increase the flow rate of the refrigerant during operation of the motor.

The electric motor of the present invention is an electric motor used for a compressor, and has a yoke portion extending in the circumferential direction around the axis and a plurality of yoke portions extending from the yoke portion toward the axis and arranged in the circumferential direction. A stator core having a tooth, a stator having a winding wound around a plurality of teeth of the stator core, and a rotor having a number of poles P arranged inside the stator in the radial direction about the axis. Be prepared. When the number of a plurality of teeth is represented by S, S / P ≧ 6 holds. The yoke portion has a refrigerant passage for circulating the refrigerant gas compressed in the compressor in the direction of the axis. The refrigerant passage has a through hole penetrating the yoke portion in the axial direction, and a notch formed on the outer periphery of the yoke portion over the entire area in the axial direction of the yoke portion. A plurality of through holes and notches are formed alternately in the circumferential direction. The through hole is located radially outside the coil end of the winding. The stator core further has a plurality of slots, each of which is located between two tees adjacent in the circumferential direction among the plurality of teeth. In each slot, the width Ws in the circumferential direction is constant in the radial direction. Each tooth has a circumferential width W1 at the radial inner end and a circumferential width W2 at the radial outer end. Assuming that the shortest distance from the slot to the through hole is T1, Wt = (W1 + W2) / 2, T1 ≧ (W1 + W2) / 4, and Wt / Ws ≧ 1 are established.

In the present invention, since the number S of teeth and the number P of poles satisfy S / P ≧ 6, it is possible to reduce the harmonics of the induced voltage generated in the winding and suppress vibration and noise. Further, since the winding is wound around the tooth by a wave winding, there is little protrusion of the winding to the outside in the radial direction. Therefore, the flow rate of the refrigerant passing through the refrigerant passage provided in the yoke portion is not obstructed by the winding, and the flow rate of the refrigerant can be increased.

It is sectional drawing which shows the electric motor of Embodiment 1. FIG. It is a perspective view which shows the electric motor which the winding | winding of Embodiment 1 is not wound. It is a perspective view which shows the electric motor which wound the winding of Embodiment 1. FIG. It is a schematic diagram (A) for explaining the dimension of each part of the electric motor of Embodiment 1, and a schematic diagram (B) which shows by enlarging the circumference of a tooth. FIG. 3A is a schematic diagram showing the flow of magnetic flux in the teeth and the yoke of the first embodiment, and FIG. 3B is an enlarged schematic diagram showing the periphery of the teeth. It is a perspective view which shows the winding | winding of Embodiment 1. FIG. It is a schematic diagram which shows the part of the winding of Embodiment 1 enlarged. It is a perspective view which shows one winding part of the winding of Embodiment 1. FIG. It is a perspective view which shows the two winding part of the winding of Embodiment 1. FIG. It is a perspective view which shows the winding part inserted into the same slot of the stator of Embodiment 1. FIG. It is sectional drawing which shows the electric motor of the comparative example. It is a graph which shows the relationship between the ratio S / P of the number of slots S and the number of poles P, and the winding coefficient of a fundamental wave. It is a graph which shows the relationship between S / P and a 3rd order winding coefficient. It is a graph which shows the relationship between S / P and the fifth-order winding coefficient. It is a graph which shows the relationship between S / P, and the ratio W2 / W1 of the width of the root portion and the width of the tip portion of a tooth. It is a graph which shows the relationship between S / P and the ratio of a tooth width and a slot width. It is a graph which compares and shows the copper loss in Embodiment 1 and the comparative example. It is sectional drawing (A), (B), (C) and (D) which shows the electric motor of the modification of Embodiment 1. It is a vertical sectional view which shows the compressor to which the electric motor of Embodiment 1 is applied. It is a figure which shows the air conditioner provided with the compressor of FIG.

Embodiment 1.
<Motor configuration>
FIG. 1 is a cross-sectional view showing the electric motor 100 of the first embodiment. The electric motor 100 is a brushless DC motor and is used in the compressor 500 (FIG. 19) described later. Further, the electric motor 100 is a permanent magnet embedded type electric motor in which a permanent magnet 32 is embedded in a rotor 3.

The motor 100 has a stator 1 and a rotor 3 rotatably provided inside the stator 1. An air gap is provided between the stator 1 and the rotor 3. Further, the stator 1 is incorporated in the cylindrical shell 4 of the compressor 500.

The rotor 3 has a cylindrical rotor core 30 and a permanent magnet 32 attached to the rotor core 30. The rotor core 30 is formed by laminating, for example, electromagnetic steel sheets having a thickness of 0.1 to 0.7 mm in the direction of the rotation axis and fixing them by caulking or the like. A circular shaft hole 34 is formed in the radial center of the rotor core 30. A shaft 35, which is a rotating shaft, is fixed to the shaft hole by press fitting. The axis C1 which is the central axis of the shaft 35 forms the rotation axis of the rotor 3.

Hereinafter, the direction of the axis C1 of the shaft 35 is referred to as “axial direction”. Further, the circumferential direction around the axis C1 (indicated by the arrow R1 in FIG. 1) is referred to as a "circumferential direction". The radial direction centered on the axis C1 is referred to as "diameter direction".

A plurality of magnet insertion holes 31 are formed at equal intervals in the circumferential direction along the outer circumference of the rotor core 30. The number of magnet insertion holes 31 is four here. The magnet insertion hole 31 penetrates the rotor core 30 in the axial direction. Further, the magnet insertion hole 31 extends linearly along the outer peripheral surface of the rotor core 30.

A permanent magnet 32 is arranged inside the magnet insertion hole 31. The permanent magnet 32 is a flat plate-shaped member having a length in the axial direction, a width in the circumferential direction, and a thickness in the radial direction. One permanent magnet 32 is arranged in one magnet insertion hole 31. However, a configuration in which a plurality of permanent magnets 32 are arranged in one magnet insertion hole 31 is also possible.

Here, the number of poles P of the rotor 3 is 4. However, the number of poles P of the rotor 3 is not limited to 4, and may be 2 or more. Further, here, one magnet insertion hole 31 and one permanent magnet 32 correspond to one magnetic pole, but a plurality of magnet insertion holes 31 may correspond to one magnetic pole, and one magnet insertion hole 31 may correspond to one magnetic pole. A plurality of permanent magnets 32 may correspond to the magnetic poles.

The center of the magnet insertion hole 31 in the circumferential direction is the polar center. Here, the magnet insertion hole 31 extends in a direction orthogonal to a radial straight line (also referred to as a magnetic pole center line) passing through the pole center. The space between the adjacent magnet insertion holes 31 is between the poles.

The permanent magnet 32 is composed of a rare earth sintered magnet containing neodymium (Nd), iron (Fe), boron (B) and dysprosium (Dy). Since the rare earth sintered magnet has a high residual magnetic flux density, it is possible to reduce the axial length of the rotor 3 required to obtain a desired output.

Each permanent magnet 32 is magnetized so that the radial outer side and the radial inner side have opposite magnetic poles. Further, the permanent magnets 32 adjacent to each other in the circumferential direction have magnetic poles opposite to each other directed toward the outer peripheral side.

Flux barriers 33 are formed at both ends of the magnet insertion hole 31 in the circumferential direction. The flux barrier 33 is a gap extending in the radial direction from the circumferential end of the magnet insertion hole 31 toward the outer periphery of the rotor core 30. The flux barrier 33 is provided to suppress the leakage flux between adjacent magnetic poles (that is, the magnetic flux flowing through the poles).

<Structure of stator>
The stator 1 has a stator core 10 and a winding 2 (FIG. 3) wound around the stator core 10 by a wave winding. The stator core 10 is formed by laminating, for example, electromagnetic steel sheets having a thickness of 0.1 to 0.7 mm in the axial direction and fixing them by a caulking portion 17.

The stator core 10 has an annular yoke portion 11 and a plurality of teeth 12 extending radially inward from the yoke portion 11. In the example shown in FIG. 1, the number of teeth 12 is 36. The width (length in the circumferential direction) of the teeth 12 becomes narrower toward the tip of the teeth 12, that is, toward the inside in the radial direction.

Slots 13 are formed between the teeth 12 adjacent to each other in the circumferential direction. The slot 13 is a portion for accommodating the winding 2 wound around the teeth 12, and extends in the radial direction. The number of slots 13 is the same as the number of teeth 12, and is referred to as the number of slots S. In the example shown in FIG. 1, the number of slots S is 36, and nine slots 13 correspond to one magnetic pole of the rotor 3.

In the case of a three-phase distributed winding, the number of slots S is 3n (n is a natural number) times the number of poles P. Therefore, the ratio (ratio) S / P of the number of slots S to the number of poles P is, for example, 3, 6, 9, 12, 15, and the like. For the sake of simplicity, S / P is also referred to as a ratio of the number of slots S to the number of poles P.

The stator core 10 is formed with a through hole 15 that penetrates the stator core 10 in the axial direction. Through holes 15 are formed at a plurality of locations in the circumferential direction in the yoke portion 11. Here, six through holes 15 are arranged at equal intervals in the circumferential direction. The through hole 15 constitutes a refrigerant passage through which the refrigerant passes in the axial direction. Since the through hole 15 is a hole through which the refrigerant gas passes, it is also called an air hole. The cross-sectional shape of the through hole 15 is circular here, but is not limited to a circular shape.

FIG. 2 is a perspective view showing the motor 100 in a state where the winding 2 is not wound around the stator core 10. As shown in FIG. 2, the yoke portion 11 of the stator core 10 has a cylindrical outer peripheral surface 18, and the outer peripheral surface 18 is fitted to the inner peripheral surface 41 of the cylindrical shell 4.

A notch 16 is formed on the outer peripheral surface 18 of the stator core 10. The notch portion 16 is a cylindrical outer peripheral surface 18 cut out in a plane parallel to the axis C1. In other words, the notch portion 16 has a shape (that is, a string-like shape) in which the outer periphery of the yoke portion 11 is linearly cut out on the plane orthogonal to the axis C1.

The notch portions 16 are formed at a plurality of points in the circumferential direction in the yoke portion 11. Here, six notches 16 are arranged at equal intervals in the circumferential direction. The notch portion 16 constitutes a refrigerant passage through which the refrigerant passes in the axial direction between the inner peripheral surface 41 of the shell 4.

That is, the through hole 15 and the notch portion 16 of the stator core 10 both form a refrigerant passage. Since the refrigerant passage (through hole 15 and the notch portion 16) is formed in the stator 1 in this way, the refrigerant can easily flow as compared with the case where the refrigerant passage is formed in the rotor 3.

The number of through holes 15 and the number of cutouts 16 are the same (6 in this case), and they are arranged alternately in the circumferential direction. That is, the through hole 15 is located between the notches 16 adjacent to each other in the circumferential direction, and the notch portion 16 is located between the through holes 15 adjacent to each other in the circumferential direction. As a result, the distribution of the refrigerant flow rate in the circumferential direction becomes uniform.

Further, the caulking portion 17 for fixing the electromagnetic steel sheets of the stator core 10 to each other is formed in the yoke portion 11. This is so that the caulking portion 17 does not obstruct the flow of magnetic flux. Further, a current easily flows in the caulking portion 17 in the axial direction, and when the caulking portion 17 is formed on the teeth 12, an eddy current is generated due to a time change of the magnetic flux flowing through the teeth 12. The caulking portion 17 is formed, for example, on the outer peripheral side of the yoke portion 11 at a position corresponding to the center in the circumferential direction of the notch portion 16.

FIG. 3 is a perspective view showing the motor 100 in which the winding 2 is wound around the stator core 10. The winding 2 is wound around the 36 teeth 12 of the stator core 10 by a wave winding. Since the winding 2 is wound by a wave winding, the amount of protrusion from the teeth 12 to the outside in the radial direction is small. Therefore, the winding 2 does not obstruct the flow of the refrigerant passing through the through hole 15 and the notch 16 which are the refrigerant passages.

Further, since the winding 2 is wound by a wave winding, the amount of protrusion of the winding 2 from the stator core 10 in the axial direction is smaller than that in the case where the winding 2 is wound concentrically. That is, since the coil end portion that does not contribute to the generation of the driving force is small in the total length of the winding 2, the desired torque can be obtained with a smaller current, and the motor efficiency is improved. Further, since the amount of protrusion of the winding 2 in the axial direction is small, the length of the electric motor 100 in the axial direction is short.

FIG. 4A is a schematic diagram for explaining the dimensions of each part of the electric motor 100. The diameter of the stator 1, that is, the diameter D1 of the stator core 10, is set to a length that fits into the inner peripheral surface 41 of the shell 4. The diameter of the rotor 3 (that is, the diameter of the rotor core 30) D2 is, for example, 60 mm to 120 mm.

FIG. 4B is an enlarged schematic view showing a part of the stator 1. As described above, the width of the teeth 12 becomes narrower as it approaches the tip portion 12a of the teeth 12. Assuming that the width at the tip portion 12a (diameter inner end portion) of the teeth 12 is W1 and the width at the root portion 12b (diameter outer end portion) of the teeth 12 is W2, W1 <W2 holds. The average of the widths W1 and W2 is referred to as the average width Wt of the teeth 12. That is, Wt = (W1 + W2) / 2. The average width Wt of the teeth 12 is the width of the magnetic path that flows in the teeth 12 in the radial direction, and is also simply referred to as the width Wt.

The radial length of the teeth 12 (that is, the distance from the root portion 12b to the tip portion 12a) is defined as H1. H1 is also the length of slot 13. Further, the distance (yoke width) from the root portion 12b of the teeth 12 to the outer peripheral surface 18 of the yoke portion 11 is defined as H2. The yoke width H2 is the width of the magnetic path flowing in the circumferential direction in the yoke portion 11.

Windings 2 are arranged in a row in the slot 13. The circumferential width Ws of the slot 13 is set to such a width that the windings 2 are arranged in a row. That is, the slot 13 has a rectangular shape having a width Ws in the circumferential direction and a length H1 in the radial direction. The radially inner end of the slot 13 is the opening 13a into which the winding 2 is inserted, and the radially outer end is the termination 13b.

FIG. 5A is a schematic diagram showing the flow of magnetic flux in the teeth 12 and the yoke portion 11. The magnetic flux from the permanent magnet 32 of the rotor 3 flows into the teeth 12 from the tip portion 12a, flows radially outward in the teeth 12, flows into the yoke portion 11 from the root portion 12b, and flows in the yoke portion 11 on both sides in the circumferential direction. Flow to.

FIG. 5B is an enlarged schematic view showing the teeth 12, the slot 13, and the yoke portion 11. The through hole 15 is formed in the yoke portion 11 at a position facing the root portion 12b of the teeth 12. More specifically, the through hole 15 is formed on a radial straight line C2 passing through the circumferential center of the teeth 12. The shortest distance from the slot 13 to the through hole 15 is T1.

The shortest distance T1 from the slot 13 to the through hole 15 is set to be longer than 1/2 of the average width Wt of the teeth 12. This is to prevent the magnetic flux flowing from the teeth 12 into the yoke portion 11 from being obstructed as much as possible. Since the average width Wt of the teeth 12 is (W1 + W2) / 2, T1 is set so as to satisfy T1 ≧ (W1 + W2) / 4.

<Composition of winding>
Next, winding 2 will be described. The winding 2 is a conductor (for example, copper) coated with a corrosion-resistant coating, for example, a polyesterimide or polyamideimide coating. This is because the winding 2 is in contact with the refrigerant circulating inside the compressor 500 in which the motor 100 is provided.

FIG. 6 is a schematic diagram showing only the winding 2 wound by the wave winding. The winding 2 has a straight portion 22 inserted into the slot 13 (FIG. 1), a coil end portion 21 extending in the circumferential direction at one end surface in the axial direction of the rotor core 30, and the other end surface in the axial direction of the rotor core 30. It has a coil end portion 23 extending in the circumferential direction. Here, it is assumed that the eight winding portions 20 of the winding 2 are inserted in one slot 13 (FIG. 1).

FIG. 7 is an enlarged view showing a part of the coil end portion 21 of the winding 2. In the coil end portion 21, nine winding portions 20 are wound around the same winding position in the radial direction (for example, the innermost peripheral position) while shifting the circumferential position by one slot. Three of the nine winding portions 20 wound around the innermost circumference are referred to as winding portions 20a, 20b, 20c.

FIG. 8 is a schematic view showing one winding portion 20a taken out. The winding portion 20a has two coil end portions 21a, four straight line portions 22a, and two coil end portions 23a. The winding portion 20a is wound so as to straddle the nine teeth 12. That is, the straight portion 22a of the winding portion 20a is inserted into every nine slots 13.

The coil end portion 21a extends so as to connect one end in the axial direction (upper end in FIG. 8) of the straight portion 22a, and the coil end portion 23a extends from the other end in the axial direction (lower end in FIG. 8) of the straight portion 22a. It extends to connect. The coil end portion 21a and the coil end portion 23a are alternately arranged in the circumferential direction about the axis C1.

At the center of the coil end portion 21a in the circumferential direction, a nose portion 25a that is displaced by the displacement amount E1 in the radial direction is provided. As shown by the arrow A1 in FIG. 8, the coil end portion 21a extends clockwise around the axis C1 and is displaced inward in the radial direction by the displacement amount E1 at the nose portion 25a, and the arrow A1 again. It extends in the direction indicated by.

Further, at the central portion of the coil end portion 23a in the circumferential direction, a nose portion 26a that is displaced by the displacement amount E1 in the radial direction is provided. As shown by the arrow A2 in FIG. 8, the coil end portion 23a extends clockwise around the axis C1, is displaced outward by the displacement amount E1 in the nose portion 26a, and is again displaced by the arrow A2. It extends in the direction indicated by.

FIG. 9 is a schematic view showing two winding portions 20a and 20b. Similar to the winding portion 20a, the winding portion 20b has two coil end portions 21b, four linear portions 22b, and two coil end portions 23b.

The straight line portion 22b of the winding portion 20b is located at a position shifted clockwise by one slot about the axis C1 with respect to the straight line portion 22a of the winding portion 20a. Similar to the nose portions 25a and 26a of the coil end portions 21a and 23a, the nose portions 25b and 26b are formed at the central portions of the coil end portions 21b and 23b in the circumferential direction.

The coil end portions 21a and 21b of the winding portions 20a and 20b overlap in the axial direction and extend in the circumferential direction, and are reversed up and down (positional relationship in the axial direction) through the nose portions 25a and 25b. Similarly, the coil end portions 23a and 23b of the winding portions 20a and 20b overlap in the axial direction and extend in the circumferential direction, and are turned upside down via the nose portions 26a and 26b. Therefore, the straight portions 22a and 22b of the winding portions 20a and 20b can be inserted into the adjacent slots 13 (FIG. 1) without interfering with each other.

Although FIG. 9 shows only the two winding portions 20a and 20b, a total of nine winding portions including these are included in the winding position (for example, the innermost peripheral position) in the same radial direction as the winding portions 20a and 20b. The winding portion 20 is wound. That is, the straight portion 22 of the winding 2 is inserted into all 36 slots 13 of the stator core 10.

FIG. 10 is a schematic diagram showing a total of eight winding portions 20 inserted into the same slot 13 as the winding portion 20a shown in FIG. The eight winding portions 20 are wound at equal intervals in the radial direction. In this way, the winding portion 20 is wound by shifting it by one slot in the circumferential direction (FIG. 9), and is also wound in the radial direction to form the winding 2 of the wave winding shown in FIG. ..

The number of winding portions 20 inserted into one slot 13 and the number of teeth 12 straddling the winding portions 20 are not limited to the examples shown in FIGS. 6 to 10, and the number of poles P is not limited. And it can be arbitrarily set according to the number of slots S.

<Comparison example>
Next, the electric motor 100E of the comparative example will be described. FIG. 11 is a cross-sectional view showing the electric motor 100E of the comparative example. The motor 100E of the comparative example has a stator 1E and a rotor 3. The rotor 3 is configured in the same manner as the rotor 3 of the first embodiment. The stator 1E has a stator core 10E and a winding 2E. The stator core 10E has an annular yoke portion 11E and twelve teeth 12E extending radially inward from the yoke portion 11E. Slots 13E are formed between the teeth 12E adjacent to each other in the circumferential direction.

In the motor 100E of the comparative example, the winding 2E is concentrically wound around the teeth 12E. The winding 2E wound by concentric winding largely protrudes radially outward from the teeth 12E. Therefore, even if a through hole or the like for passing the refrigerant is formed in the yoke portion 11E, the flow of the refrigerant is obstructed by the winding 2E. Further, the winding 2E wound by concentric winding has a large amount of protrusion in the axial direction from the stator core 10E, and therefore the coil end portion becomes large. That is, the length of the winding portion that does not contribute to the generation of torque is large in the total length of the winding 2E, so that the motor efficiency is low.

<Effect of reducing harmonic components of induced voltage>
Next, a preferable range of the ratio S / P between the number of slots S and the number of poles P will be described. First, the relationship between the S / P and the effect of reducing the harmonic component of the induced voltage will be described.

When the rotor 3 rotates, a voltage (induced voltage) is induced in the winding 2 of the stator 1 by the magnetic field of the permanent magnet 32. The fundamental wave component of the induced voltage contributes to torque generation, but the harmonic component becomes torque ripple, which causes vibration and noise of the motor 100. Therefore, suppressing the harmonic component of the induced voltage becomes an issue.

The fundamental and harmonic components of the induced voltage can be evaluated by the winding coefficient. The winding coefficient is calculated by multiplying the short-knot winding coefficient Kp and the distributed winding coefficient Kd. The short-knot winding coefficient Kp is calculated by the following equation (1) based on the order, the number of poles P, the number of slots S, and the coil throw (the number of teeth across the winding 2).
Kp = sin (order x 180 x number of poles / number of slots x coil throw / 2) ... (1)

The distributed winding coefficient Kd is calculated by the following equation (2) based on the phase difference α between the windings.
Kd = cos (order x α / 2) ... (2)
Here, the phase difference α between the windings is obtained by the following equation (3).
α = 180 x number of poles / number of slots ・ ・ ・ (3)

In the motor 100 shown in FIG. 1, the ratio S / P of the number of slots S and the number of poles P was changed, and the winding coefficients of the fundamental wave, the third harmonic and the fifth harmonic were obtained, respectively. FIG. 12 is a graph showing the relationship between the S / P and the winding coefficient of the fundamental wave. FIG. 13 is a graph showing the relationship between the S / P and the third-order winding coefficient. FIG. 14 is a graph showing the relationship between the S / P and the fifth-order winding coefficient. In FIGS. 12, 13, and 14, the S / P values are changed to 3, 6 , 9, 12, and 15.

As shown in FIG. 12, the winding coefficient of the fundamental wave (first order) is 1 when the S / P is 3 , and becomes 0. It gradually decreases from 95 to 0.96.

Further, as shown in FIG. 13, the third-order winding coefficient is 1 when the S / P is 3, becomes 0.7 when the S / P is 6, and the S / P becomes 0.7. As it increases to 9 , 12, and 15, it decreases to 0.65.

Further, as shown in FIG. 14, the fifth-order winding coefficient is 1 when the S / P is 3, and is reduced to 0.25 when the S / P is 6, and the S / P is reduced to 0.25. As it increases to 9 , 12, and 15, it decreases to 0.2.

When the S / P is 3, since the winding coefficient of the fundamental wave is large, the winding interlinkage magnetic flux can be fully utilized, which is advantageous in obtaining a high torque. However, since the winding coefficients of the third and fifth orders are also large, harmonic components may be superimposed on the induced voltage, and vibration and noise of the motor 100 may be generated.

On the other hand, when the S / P is 6 or more, the winding coefficient of the fundamental wave is reduced, but the winding coefficients of the third and fifth orders are also reduced, so that the harmonics of the induced voltage are reduced and the motor is used. It is possible to suppress 100 vibrations and noises.

From this result, it can be seen that when the S / P is 6 or more (that is, S / P ≧ 6), the harmonics of the induced voltage can be reduced and the vibration and noise of the motor 100 can be suppressed.

<Teeth shape>
Next, the relationship between the S / P and the ratio W2 / W1 of the width W2 of the root portion 12b to the width W1 of the tip portion 12a of the teeth 12 will be described. In the case of a wave winding, since the windings 2 are inserted in a row in the slot 13 as shown in FIG. 4 (B), the shape of the slot 13 (more specifically, the cross-sectional shape orthogonal to the axis C1). Becomes a rectangle. Therefore, the shape of the teeth 12 between the adjacent slots 13 becomes a trapezoidal shape.

When the shape of the teeth 12 is closer to a rectangle, the bias of the magnetic flux density distribution in the teeth 12 can be suppressed, so that local magnetic saturation or an increase in iron loss in the teeth 12 can be suppressed. Therefore, better magnetic characteristics can be obtained when the ratio W2 / W1 of the width W2 of the root portion 12b to the width W1 of the tip portion 12a of the teeth 12 is closer to 1.

Generally, the rotor outer diameter of a compressor for a compressor in which distributed winding (including wave winding) is used is 60 to 120 mm. Therefore, here, the outer diameter D2 of the rotor 3 is changed to 60, 80, 100, 120 mm. rice field. FIG. 15 is a graph showing the relationship between S / P and W2 / W1 when the outer diameter D2 of the rotor 3 is changed to 60, 80, 100, 120 mm.

From FIG. 15, when the outer diameter D2 of the rotor 3 is 80 to 120 mm, W2 / W1 becomes the maximum when the S / P is 3, and W2 increases as the S / P increases to 6, 9, 12, and 15. / W1 decreases and approaches 1. Further, when the S / P is 12 or more, the decrease rate of W2 / W1 becomes flat.

On the other hand, when the outer diameter D2 of the rotor 3 is 60 mm, W2 / W1 decreases as the S / P increases to 3, 6 and 9, but when the S / P increases from 12 to 15, W2 / W1 is greatly increased, and when S / P is 15, W2 / W1 becomes maximum.

That is, when the S / P is 15, the shape of the teeth 12 greatly deviates from the rectangle when the rotor 3 has a small diameter, which is not desirable in terms of suppressing the bias of the magnetic flux density distribution in the teeth 12.

From this result, it can be seen that 6 ≦ S / P ≦ 12 is desirable in order to suppress the bias of the magnetic flux density distribution in the teeth 12.

<Ratio of tooth width and slot width>
Next, the relationship between the S / P and the ratio of the width Wt of the teeth 12 to the width Ws of the slot 13 (Wt / Ws) will be described. The width Wt of the teeth 12 is (W1 + W2) / 2 described above. If the width Wt of the teeth 12 is narrow, magnetic saturation may occur in the teeth 12 and lead to an increase in iron loss. Therefore, it is desirable that the width Wt of the teeth 12 is wide. In particular, it is desirable that the ratio Wt / Ws of the width Wt of the teeth 12 to the width Ws of the slot 13 is 1 or more.

FIG. 16 is a graph showing the relationship between S / P and Wt / Ws when the outer diameter D2 of the rotor 3 is changed to 60, 80, 100, 120 mm. As shown in FIG. 16, when the outer diameter D2 of the rotor 3 is 60, 80, 100, or 120 mm, the larger the S / P, the smaller the Wt / Ws tends to be.

Further, when the S / P is 15, the Wt / Ws is less than 1 when the outer diameter D2 of the rotor 3 is 60 mm (in other words, the width Wt of the teeth 12 is narrower than the width Ws of the slot 13). Therefore, it is not desirable in terms of suppressing iron loss.

From this result, it can be seen that 6 ≦ S / P ≦ 12 is desirable in order to suppress the magnetic saturation in the teeth 12 and improve the iron loss.

If the width Ws of the slot 13 is too narrow with respect to the width Wt of the teeth 12, the wire diameter of the winding 2 becomes smaller and the current density flowing through the winding 2 increases. As the current density increases, the heat resistance of the winding must be improved, which leads to an increase in manufacturing cost. Therefore, it is desirable that the width Wt of the teeth 12 is 6 times or less the width Ws of the slot 13. That is, 1 ≦ Wt / Ws ≦ 6 is desirable.

<Reduction of copper loss>
Next, the effect of reducing copper loss due to the winding 2 being wound by a wave winding in the first embodiment will be described. FIG. 17 compares the copper loss between the motor 100E of the comparative example (FIG. 11) in which the winding 2 is wound concentrically and the motor 100 of the first embodiment in which the winding 2 is wound by a wave winding. It is a graph which shows the result.

Here, the copper loss in the motor 100E (FIG. 11) of the comparative example was set to 100%, and the degree to which the copper loss in the motor 100 of the first embodiment was reduced was measured. As shown in FIG. 17, with respect to the motor 100E of the comparative example, in the first embodiment, the copper loss was 65.6%, and a decrease of 34.4% was confirmed. This is because when the winding 2 is a wave winding, the peripheral length of the winding 2 is shorter than that of the concentric winding.

<Effect of embodiment>
As described above, in the motor 100 of the first embodiment of the present invention, the winding 2 is wound around the teeth 12 of the stator 1 by a wave winding, and the number of slots S and the number of poles P satisfy S / P ≧ 6. The yoke portion 11 of the stator core 10 is provided with a refrigerant passage (that is, a through hole 15 and a notch portion 16) for allowing the refrigerant to flow in the axial direction. Therefore, it is possible to reduce the harmonics of the induced voltage generated in the winding 2 when the rotor 3 is rotated, thereby suppressing the vibration and noise of the motor 100.

Further, since the winding 2 is wound around the teeth 12 by a wave winding, there is little protrusion of the winding 2 to the outside in the radial direction. Therefore, the flow rate of the refrigerant passing through the through hole 15 and the notch 16 is not obstructed by the winding 2, and a sufficient flow rate of the refrigerant can be secured.

Further, since the winding 2 is wound around the teeth 12 by a wave winding, the amount of protrusion of the winding 2 from the stator core 10 in the axial direction is small. Therefore, the coil end portion can be made smaller to improve the efficiency of the motor, and the size of the motor 100 can be reduced.

In particular, for large equipment such as commercial air conditioners, there is a demand for a compact and lightweight electric motor 100 with less vibration and noise. The motor 100 of the first embodiment is particularly suitable for such an application.

Further, when the number of slots S and the number of poles P satisfy 6 ≦ S / P ≦ 12, the shape of the teeth 12 can be made closer to a rectangle, local magnetic saturation is suppressed, and iron loss is reduced. be able to.

Further, since the winding 2 is covered with polyesterimide or polyamideimide (corrosion resistant material), it is possible to prevent corrosion by the refrigerant circulating in the compressor 500.

Further, the rotor 3 has a permanent magnet 32 composed of a rare earth sintered magnet, and since the rare earth sintered magnet has a high residual magnetic flux density and coercive force, the efficiency of the electric motor 100 is improved and the demagnetization strength is improved. be able to.

Further, since the caulking portion 17 is formed on the yoke portion 11, it does not interfere with the flow of magnetic flux in the teeth 12 as in the case where the caulking portion 17 is formed on the teeth 12, and sufficient strength of the stator 1 is obtained. At the same time, the efficiency of the motor can be improved.

Further, since the stator 1 has a through hole 15 that penetrates the yoke portion 11 in the direction of the axis C1, the refrigerant can easily flow through the through hole 15 and the flow rate of the refrigerant can be increased.

Further, since the width W1 at the tip portion 12a of the teeth 12, the width W2 at the root portion 12b, and the shortest distance T1 from the slot 13 to the through hole 15 satisfy T1 ≧ (W1 + W2) / 4, the teeth 12 The magnetic flux flowing into the yoke portion 11 is not obstructed as much as possible, and the efficiency of the motor can be further improved.

Further, since the stator 1 has a notch portion 16 formed on the outer periphery of the yoke portion 11 over the entire area in the direction of the axis of the yoke portion 11, the stator 1 passes between the notch portion 16 and the shell 4. The refrigerant easily flows, and the flow rate of the refrigerant can be increased.

Further, since a plurality of through holes 15 and notches 16 are provided respectively and the through holes 15 and the notches 16 are alternately formed in the circumferential direction, the distribution of the refrigerant flow rate in the circumferential direction becomes uniform. ..

<Modification example>
Next, a modified example of the first embodiment will be described. 18 (A), (B), (C) and (D) are schematic views showing the motors 100A, 100B, 100C and 100D of the modified example of the first embodiment.

In the motor 100 (FIG. 1) of the first embodiment described above, the stator 1 has both a through hole 15 and a notch portion 16. However, as in the motor 100A shown in FIG. 18A, the stator 1A may have a through hole 15 and no notch 16. In this case, the through hole 15 of the stator 1A serves as a refrigerant passage through which the refrigerant passes.

Further, as in the motor 100B shown in FIG. 18B, the stator 1B may have a notch 16 and no through hole 15. In this case, the notch 16 of the stator 1B serves as a refrigerant passage through which the refrigerant passes.

The motor 100 (FIG. 1) of the first embodiment described above has a notch portion 16 in which the cylindrical outer peripheral surface 18 of the stator 1 is cut out in a plane. However, as in the motor 100C shown in FIG. 18C, a groove 16C having a rectangular cross section may be provided on the outer peripheral surface 18 of the stator 1C. In this case, the through hole 15 and the groove 16C of the stator 1C serve as a refrigerant passage through which the refrigerant passes.

Further, as in the motor 100D shown in FIG. 18D, a groove 16D having a V-shaped cross section may be provided on the outer peripheral surface 18 of the stator 1D . In this case, the through hole 15 and the groove 16D of the stator 1D serve as a refrigerant passage through which the refrigerant passes. It should be noted that the motors 100C and 100D shown in FIGS. 18C and 18D may be configured without the through hole 15.

In the first embodiment and each modification described above, the number of through holes 15 and the number of cutouts 16 can be arbitrarily set. That is, at least one through hole 15 or at least one notch portion 16 may be formed in the yoke portion 11 of the stator 1.

<Compressor>
Next, the compressor using the electric motor 100 of the first embodiment described above will be described. FIG. 19 is a cross-sectional view showing the configuration of a compressor (scroll compressor) 500 using the motor 100 of the first embodiment described above.

The compressor 500 is a scroll compressor, and in a closed container 502, the compression mechanism 510, the electric motor 100 for driving the compression mechanism 510, the main shaft 501 connecting the compression mechanism 510 and the electric motor 100, and the compression of the main shaft 501 are performed. It includes a subframe 503 that supports the opposite end (sub-shaft portion) of the mechanism 510, and a lubricating oil 504 that is stored in the oil sump 505 at the bottom of the closed container 502.

The compression mechanism 510 has a fixed scroll 511 and a swing scroll 512 attached to the spindle 501. Both the fixed scroll 511 and the swing scroll 512 have a spiral portion, and a spiral compression chamber 516 is formed between them. The compression mechanism 510 further includes an old dam ring 513 that regulates the rotation of the swing scroll 512 to swing the swing scroll 512, a compliant frame 514 to which the swing scroll 512 is attached, and a guide frame that supports them. It is equipped with 515.

A suction pipe 506 penetrating the closed container 502 is press-fitted into the fixed scroll 511. Further, a discharge pipe 507 is provided which penetrates the closed container 502 and discharges the high-pressure refrigerant gas discharged from the discharge port 511a of the fixed scroll 511 to the outside.

The closed container 502 has a cylindrical shell 4 (FIG. 1), and the motor 100 of the first embodiment is attached to the inner peripheral side of the shell 4. A glass terminal 508 for electrically connecting the stator 1 of the motor 100 and the drive circuit is fixed to the closed container 502 by welding. The spindle 501 is the shaft 35 of the motor 100 (FIG. 1).

The operation of the compressor 500 is as follows. When the motor 100 rotates, the spindle 501 (shaft 35) rotates together with the rotor 3. When the spindle 501 rotates, the swing scroll 512 swings, changing the volume of the compression chamber 516 between the fixed scroll 511 and the swing scroll 512. As a result, the refrigerant gas is sucked into the compression chamber 516 from the suction pipe 506 and compressed.

The high-pressure refrigerant gas compressed in the compression chamber 516 is discharged into the closed container 502 from the discharge port 511a of the fixed scroll 511, and is discharged to the outside from the discharge pipe 507. Further, a part of the refrigerant gas discharged from the compression chamber 516 into the closed container 502 passes through the through hole 15 and the notch portion 16 (FIG. 1) of the stator 1 to cool the motor 100 and the lubricating oil 504.

As described above, since the electric motor 100 of the first embodiment can suppress the harmonics of the induced voltage, it is possible to suppress the vibration and noise during the operation of the compressor 500. Further, in the electric motor 100 of the first embodiment, since the winding 2 is wound by a wave winding, a sufficient flow rate of the refrigerant passing through the through hole 15 and the notch 16 (FIG. 1) is secured for the electric motor 100. The cooling efficiency can be improved and the operational stability of the compressor 500 can be improved.

The compressor 500 is not limited to the motor 100 of the first embodiment, and the motors 100A, 100B, 100C, 100D (FIG. 18) of each modification may be used. Further, although the scroll compressor has been described here as an example of the compressor, the electric motor 100 (100A to 100D) of the first embodiment and each modification may be applied to a compressor other than the scroll compressor.

<Air conditioner>
Next, an air conditioner (refrigeration cycle device) having the compressor 500 shown in FIG. 19 will be described. FIG. 20 is a diagram showing the configuration of the air conditioner 400. The air conditioner 400 shown in FIG. 20 includes a compressor 401, a condenser 402, a throttle device (decompression device) 403, and an evaporator 404. The compressor 401, the condenser 402, the throttle device 403 and the evaporator 404 are connected by a refrigerant pipe 407 to form a refrigeration cycle. That is, the refrigerant circulates in the order of the compressor 401, the condenser 402, the throttle device 403, and the evaporator 404.

The compressor 401, the condenser 402, and the throttle device 403 are provided in the outdoor unit 410. The compressor 401 is composed of the compressor 500 shown in FIG. The outdoor unit 410 is provided with an outdoor blower 405 that supplies outdoor air to the condenser 402. The evaporator 404 is provided in the indoor unit 420. The indoor unit 420 is provided with an indoor blower 406 that supplies indoor air to the evaporator 404.

The operation of the air conditioner 400 is as follows. The compressor 401 compresses and sends out the sucked refrigerant. The condenser 402 exchanges heat between the refrigerant flowing in from the compressor 401 and the outdoor air, condenses the refrigerant, liquefies it, and sends it to the refrigerant pipe 407. The outdoor blower 405 supplies outdoor air to the condenser 402. The throttle device 403 adjusts the pressure of the refrigerant flowing through the refrigerant pipe 407 by changing the opening degree.

The evaporator 404 exchanges heat between the refrigerant reduced to a low pressure by the throttle device 403 and the air in the room, causes the refrigerant to take heat of the air, evaporate (vaporize) it, and send it to the refrigerant pipe 407. The indoor blower 406 supplies the indoor air to the evaporator 404. As a result, the cold air whose heat has been taken away by the evaporator 404 is supplied to the room.

Since the electric motor 100 described in the first embodiment and the modified example is applied to the compressor 401 (compressor 500 in FIG. 19), vibration and noise during operation of the air conditioner 400 can be suppressed. Further, the stability of the operation of the compressor 401 during the operation of the air conditioner 400 can be improved, and the operating efficiency can be improved.

The compressor 500 to which the motors 100 (100A to 100D) of the first embodiment and each modification are applied is not limited to the air conditioner 400 shown in FIG. 20, and may be used for other types of air conditioners. good.

Although the preferred embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and various improvements or modifications are made without departing from the gist of the present invention. be able to.

1,1A, 1B, 1C, 1D stator, 2 windings, 3 rotors, 4 shells, 10,10E stator cores, 11 yokes, 12 teeth, 12a tips, 12b roots, 13 slots, 15 through holes, 16 cuts. Notch, 16C, 16D groove, 17 caulking part, 18 outer peripheral surface , 20,20a, 20b, 20c winding part, 21,21a, 21b coil end part, 22,22a, 22b straight part, 23,23a, 23b coil End part, 25a, 25b nose part, 26a, 26b nose part, 30 rotor core, 31 magnet insertion hole, 32 permanent magnet, 33 flux barrier, 34 shaft hole, 35 shaft, 100, 100A, 100B, 100C, 100D motor, 400 Air conditioner, 405 outdoor blower, 406 indoor blower , 410 outdoor unit, 420 indoor unit, 500 scroll compressor (compressor), 501 spindle, 502 closed container, 510 compression mechanism.

Claims (10)

It is an electric motor used for compressors.
A stator core having a yoke portion extending in the circumferential direction centered on the axis, and a plurality of teeth extending from the yoke portion toward the axis and arranged in the circumferential direction.
A stator comprising a winding wound around the plurality of teeth of the stator core.
A rotor having a number of poles P arranged inside the stator in the radial direction about the axis is provided.
When the number of the plurality of teeth is represented by S, S / P ≧ 6 is established.
The yoke portion has a refrigerant passage through which the refrigerant gas compressed in the compressor flows in the direction of the axis, and the refrigerant passage has a through hole penetrating the yoke portion in the direction of the axis and the yoke. The outer periphery of the portion has a notch formed over the entire area of the yoke portion in the direction of the axis.
The through holes and the notches are both formed in a plurality and alternately in the circumferential direction, and the through holes are located outside the coil end portion of the winding in the radial direction.
The stator core further has a plurality of slots each located between the two teeth adjacent to each other in the circumferential direction among the plurality of teeth.
In each slot, the width Ws in the circumferential direction is constant in the radial direction.
Each tooth has the circumferential width W1 at the radial inner end and the circumferential width W2 at the radial outer end.
Assuming that the shortest distance from the slot to the through hole is T1,
Wt = (W1 + W2) / 2,
T1 ≧ (W1 + W2) / 4 and Wt / Ws ≧ 1
The motor that holds. The motor according to claim 1, wherein 6 ≦ S / P ≦ 12 is satisfied. The motor according to claim 1 or 2, wherein the winding has a conductor coated with polyesterimide or polyamideimide. The stator core is formed by laminating an electromagnetic steel sheet in the direction of the axis and fixing it at a caulking portion, and the caulked portion is formed on the yoke portion according to any one of claims 1 to 3. Electric motor. The motor according to any one of claims 1 to 4, wherein the cutout portion has a shape in which the outer periphery of the yoke portion is linearly cut out in a plane orthogonal to the axis line. The compressor has a cylindrical shell and has a cylindrical shell.
The motor according to any one of claims 1 to 5, wherein the stator core is fitted inside the shell. The motor according to any one of claims 1 to 6, wherein the rotor has a permanent magnet composed of a rare earth sintered magnet. The motor according to claim 7, wherein the rotor has a rotor core having a number of magnet insertion holes corresponding to the number of poles P. The motor according to any one of claims 1 to 8 and the electric motor.
A compressor provided with a compression mechanism driven by the motor. An air conditioner with a compressor, condenser, decompressor and evaporator.
The compressor is an air conditioner including the motor according to any one of claims 1 to 8 and a compression mechanism driven by the motor.

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